Highgarden is the seat of House Tyrell and the regional capital of the Reach. It is next to the river Mander. Highgarden sits on the point where the Roseroad linking Oldtown and King's Landing forks off west on the Searoad which leads to Lannisport. As King's Landing, Oldtown, and Lannisport are the first, second, and third largest cities in Westeros, heavy trade and traffic to and from Oldtown ultimately passes through Highgarden.

After Renly is assassinated, most of his bannermen from the Stormlands submit to his older brother Stannis Baratheon. However, Margaery and Loras Tyrell withdraw House Tyrell's sizable army back to Highgarden, along with the other Houses from the Reach they command.[5] A few Tyrell bannermen, however, bend the knee to Stannis.[6]